Department of Chemistry, New York University, New York, NY 10003.
Molecular Design Institute, New York University, New York, NY 10003.
Proc Natl Acad Sci U S A. 2020 Oct 27;117(43):26633-26638. doi: 10.1073/pnas.2013390117. Epub 2020 Oct 12.
Pyrethroid contact insecticides are mainstays of malaria control, but their efficacies are declining due to widespread insecticide resistance in mosquito populations, a major public health challenge. Several strategies have been proposed to overcome this challenge, including insecticides with new modes of action. New insecticides, however, can be expensive to implement in low-income countries. Here, we report a simple and inexpensive method to improve the efficacy of deltamethrin, the most active and most commonly used pyrethroid, by more than 10 times against mosquitoes. Upon heating for only a few minutes, the commercially available deltamethrin crystals, form I, melt and crystallize upon cooling into a polymorph, form II, which is much faster acting against fruit flies and mosquitoes. Epidemiological modeling suggests that the use of form II in indoor residual spraying in place of form I would significantly suppress malaria transmission, even in the presence of high levels of resistance. The simple preparation of form II, coupled with its kinetic stability and markedly higher efficacy, argues that form II can provide a powerful, timely, and affordable malaria control solution for low-income countries that are losing protection in the face of worldwide pyrethroid resistance.
拟除虫菊酯接触杀虫剂是疟疾控制的主要手段，但由于蚊虫种群中广泛存在抗药性，其功效正在下降，这是一个主要的公共卫生挑战。已经提出了几种策略来克服这一挑战，包括具有新作用模式的杀虫剂。然而，在低收入国家，新的杀虫剂实施起来可能很昂贵。在这里，我们报告了一种简单且廉价的方法，可以将最有效和最常用的拟除虫菊酯之一的溴氰菊酯的功效提高 10 多倍。只需加热几分钟，市售的溴氰菊酯晶体 I 形式就会熔化，并在冷却时结晶成多晶型 II 形式，这种形式对果蝇和蚊子的作用更快。流行病学模型表明，在室内滞留喷洒中用 II 形式代替 I 形式，即使在存在高水平抗性的情况下，也会显著抑制疟疾传播。II 形式的简单制备，加上其动力学稳定性和明显更高的功效，表明 II 形式可以为面临全球拟除虫菊酯抗性的低收入国家提供一种强大、及时且负担得起的疟疾控制解决方案。
